Musical instrument



Dec; 31, 1940. N T 2,227,100

MUSICAL INSTRUMENT Filed Aug. 11, 1959 $.Sheets-Sheet 1 ATTORNEY.

Dec. 31, 1940.

J. MANATT. 2,227,100

MUSICAL INSTRUMENT Fi led Aug. 11, 1939 3 Sheets-$heet 2 INVENTOR 22 {fun e5 Mama-ft ATTORNEY.

J. MANATT 2,227,100

IUSICAL INSTRUMENT Filed Aug. 11, 1939 3 Sheets-Sheet 5 I N VENT OR.

. J'm 65 Ma ZLZL,

ATTORNEY.

Patented Dem 31, 1940 PATENT OFFICE MUSICAL nvsraumzm James Manatt, Chicago, 111., assignor to Central Commercial Company, Chicago, 111., a corporatioii of Illinois Application August 11, 1939, Serial No. 289,541

3 Claims. (Cl. 8-i1.19)

This invention relates to electrical musical instruments for simulating organ and orchestral tones.

In my co-pending application Ser. No. 283,554,

8 filed July 10, 1939, I disclose and claim an electrical network, the characteristics of which are such that upon simultaneously playing two or more keys of a single manual and drawing one or more stops, proportionality is secured between 10 current and voltage, the current increasing in ratio to the number of keys played simultaneously without increasing the voltage and whereby the intensity of the output voltage is definitely a function of the current. In consequence of these I I circuit characteristics, notes played simultaneouse 1y add to. each other in a manner typical of the pipe organ.

The novelty present in the improvements herein set forth and claimed consists in connecting a 20 system of stops in the aforestated electrical network and employing same in conjunction with the speaking. stops of aplurality of manuals and a pedal section to produce crescendo and diminuendo effects.

25 It is well known that allmusical tones are composed of' a fundamental tone and a series of upper partials," the completeness or incompleteness of which and the prominence or weakness of said partials relative to each other and to the fundamental constitute those influences which cause the difference in tone quality between two musical sounds of the same pitch and are therefore the acoustical'factors which produce the diflerence in tone-quality between different notesand different 5 organ stops. In the embodiment of my invention herein disclosed and claimed, stops for crescendo A further feature of the invention resides in.

the forms and arrangements of stops which are progressively actuable', one at a time, from softest 50 to the loudest and are controlled from a common foot pedal.

A further object is to provide an electrical musical instrumentin which signals at different partial frequencies are produced by alternators 55 common to all stops of the instrument.

A still further object is to provide an electrical network having an expression control for the upper manual and the crescendo stops for said manual and a separate expression control for the lower manual, the pedal keyboard and the cres- 5 cendo stops for said lower manual and said pedal keyboard, the controls adapted to be actuated either singly or together from respective expression pedals and with one foot of the player while the other foot is employed to actuate all of said crescendo stops.

The invention will be more fully understood by reference to the following description when read in connection with the accompanying drawings in which: 18

Figure 1 is a schematic illustration of a portion of theelectrical networkshowing the alternators for producing signals at different partial frequencies.

Figure 2 is a view similar to Figure 1 showing 20 the portion of the network which includes the various organ stops and the crescendo stops of the instrument.

Figure 3 is a schematic view of the amplifying and sound producing systems and Figure 4 is a view inelevation of a mechanical control means for effecting actuation of the crescendo stops. 1

In carrying the invention into practice, use can be made ofnny well known system adapted to pro- 80 vide alternating voltages at the tone frequencies of the notes of the musical scale.

While I shown an organ having two manuals and a pedal keyboard, I may add to or take from\ the number of manuals without departing from the spirit and intention of my'invention and can classify the various stops to suit any desired registration. In like manner, the crescendo stops may consist of any suitable number depending upon the size and musical range of the instrument; 40

In the accompanying drawings, I show playing keys Cl and C2 of the upper manual; keys Cl and C2 of the lower manual and pedal keys C0 and practice, there will be a plurality of stops for the upper manual, a plurality of stops for the lower manual and a plurality of stops 10 for the pedal keyboard, 66

related to the rotor by a thin air dielectric.

In the accompanying drawings, I show sets of electrostatic alternators respectively distinguished from each other by the letters C, E, G and A#, each said set consisting of eight individual, continuously varying, coaxial condensers respectively numbered 0, l, 2, 3, 4, 5, 6 and 7. Each individual condenser comprises a rotor l and a pair of stators II and I2, the stators being capacitatively All rotors of an essembly are fixed to a rotary shaft I3, and as shown inFigure 1, each shaft is adapted to be polarized through a brush ll supplied with potential from a direct currentsource I5.

In practice, twelve alternator assemblies are preferably employed, each assembly designed and adapted to constitute a complete organization for the production of alternating voltages at the tone frequencies of partials in octave relation. The four assemblies shown in Figure i will therefore be considered merely a part of the total number of assemblies for a complete musical instrument. Each assembly will be driven at its own speed which will be different from that of the assembly next adjacent thereto by the twelfth root of two. In this manner, alternating voltages at the tone frequencies of the notes of the equally-tempered musical scale will be produced.

- The rotor ill of any individual condenser herein shown can be properly considered a primary electrode and the statorsa secondary electrode in which the waveform areas of the secondary electrode are adapted to be periodically scanned by capacity areas on said primary electrode to thereby electrostatically produce alternating voltage of sinusoidal waveform, the frequency of which corresponds to the note of the scale to which said condenser is assigned.

As shown in Figure l, the oppositely disposed stators II and I! of a condenser are electrically connected or tied together at- It and connected to an output conductor 11. output conductor and to a common ground connection It in the network herein employed is an impedance element l9 for controlling the exact amount of voltage necessary to be drawn from a condenser for use in said network.

Upon referring to Figure 2 of the drawings, it

is noted that each manual of the instrument is individual to a particular set of bus-bars, i. e., a system of ten bus-bars 20 is provided for the upper manual; a similar system for the lower manual and a similar system for the pedal keyboard. Reading from left to rightin said figure, the busbars 20 for said upper manual are distinguished from each other by notations indicative of different harmonic series of partial frequencies which the bus-bars serve to conduct. That is to say, the first bus-bar in the series serves as a channel for all frequencies ofthe sub-fundamental series; the second as a channel for all frequencies of the fundamental series; the third as a channel for all frequencies of the order of the organ 5th; the fourth as a channel for all frequencies of the second partial series; the fifth as a channel for all frequencies of the third partial series and so on, through and inclusive of the last bus-bar which serves as a channel for all frequencies of the 8th partial series. In series with each bus-bar is a low resistancellfl, one terminal of which is connected to said common ground. As the three systems of bus-bars are identical in every major respect and similarly connected in said network, it is thought that the description Justgiven of the system for the upper manual will suffice for all of said systems.

Connected across each In the schematic illustration of the circuits shown in Figure 2, it is noted that the playing keys Cl and C2 of the upper manual are each thereof provided with a setof switches consisting of ten similar contact elements 2|, disposed so that the upper contact element of each set will be close circuited with the bus-bar denoting the sub-fundamental frequencies when the keys are depressed. The next contact elements will be close circuited with the bus-bar denoting the fundamental frequencies and so on downwardly in the series of contact elements in each set and throughout the remaining bus-bars, to and inclusive of the bottom contact element and the bus-bar which serves as a channel for all 8th partial frequencies.

To this point in the description, it will be entirely clear to persons trained in the art to which the invention relates that upon connecting contact elements of switches of different playing keys of any manual with the continuously varying condensers or alternators in the manner herein show, contact elements of different keys are common to the same alternator, whereby when depressing a key, alternating voltages at harmonically related frequencies will be simultaneously impressed upon different bus-bars for a composite waveform of output voltage corresponding to the note assigned to said key. Hence, each output conductor has connected thereto as many branch circuits 22 as are required for the conduction of voltage of the same tone frequency to contact elements of different keys. It follows that any alternator in the system of alternators herein disclosed furnishes alternating voltage of the fundamental frequency of one or more notes assigned to the keys of different manuals, the same frequency serving as harmonics of others of said notes. In order that the flow of voltage through any branch circuit 22 can be restricted for the functional purpose to appear presently, each said branch circuit is provided with a high resistance 23 in series therewith.

Proceeding now with a description of the stop 50 of the upper manual, it will suffice to say that the contact elements 222 thereof are substantially the same as the contact elements of the switches of the aforementioned playing keys, except that each contact element has a high resistance 2| in series at its output side, whereas and with respect to said playing key switches, the aforementioned high resistances 23 are at the input sides of said contact elements 2 I. When the stop is retired as shown in Figure 2 all contact elements 222 are open circuited. when the stop is drawn, the contact elements make close circuit connection with their respective busbars 2|, whereby voltages impressed thereon can be conducted to an amplitude grading resistor 24, the latter tapped in ten logarithmic steps corresponding to 3 decibels each as indicated by corresponding numbers in Figure 2. Hence, when the stop is drawn-and key Cl and/or C2 depressed, voltages from alternators which supply said key or keys will be conducted to said resistor and their relativeintensities correctly graded. For example,

voltage at the sub-fundamental frequency of the note Cl will be conducted to tap 1. Voltage of the fundamental frequency of the said note is conducted to tap III. In like manner, others of the voltages will be conducted to said resistor as shown and graded before they are delivered to an amplifying system to be described later.

If a partial is desired at full strength, the voltage corresponding to the frequency thereof connects with the common ground conductor, as

The stop 88 for the upper manual is the same in every particular as the stop 58 and has ten contact elements 85, each of which is individual to a particular bus-bar 28. The relationship between the contacts and coacting bus-bars is the same as set iorth in the description of the contact elements 222 01' said stop 58. In series with each contact element 85 is a high resistance 88 and as shown in Figure 2, said elements are tapped to the resistor 24 for such gradation of the partials as is required for a predetermined tone quality.

It is assumed that stops 80, 98 and I88 shown in Figure 2 are coaxially related, each in coacting relation to a cam I85. The cams are mounted to turn with a common shaft I88. The sets of switches 88, 98 and I88 constitute the diflerent sets of crescendo stops and same are mounted in a case I81 as shown in Figure 4. Each switch is provided with a vertically movable arm I88 which projects through a vertical slot I89 in one wall of said case and is disposed beneath an associated cam I85. In order that the switches may be progressively actuated, the cams I85 are adjustably mounted on said shaft and adapted to be secured in set positions of angular adjustment by set screws II 8. In this manner, the orderin which the switches are close circuited can be accurately controlled. In Figure 4 I show a set of six multiple switches. for the upper and lower manuals and a set of four multiple switches for the pedal keyboard. The cams for each of said multiple switbhes are set so that when the shaft is turned-in one direction, the switches of the respectivesets will be progressively actuated. The shaftmay be operated by a foot pedal, not shown, and when the pedal is fully depressed, all of said switches will be close circuited. The speed at which the switches are open and close circuited may thereby be controlled for any desired musical results.

Assuming that four qualities are desired of the stops 88, flve of the stops 98 and three of the stops I08, the partial mixtures for the various qualities may be in accordance with the following scheme:

nected to the terminals 288 and 248 of the resistors 24 and 224. As no claim is made for said system per se, it will be sufilcient merely to mention that in order that the volume of sound.

elicited from the upper manual can be controlled independently-of the lower manual and the pedal keyboard, use is made of potentiometers 258 and 268, the operation of each of which can be conpractice, the pedals will be closely related to each other so that they can be either singly or simultaneously controlled with one foot of the player, thus leaving the other foot free for operating the respective crescendo stops. The control pedal for the crescendo stops will be situated, preferably at the right hand side of the expression pedal for said lower manual and said pedal keyboard.

Connected to the output of the amplifying system is an electrical sound producer 218 of any well known construction.

From the foregoing description, it is appreciated that-when the crescendo stops are open circuited, the stops 58, 68 and 18 can be selectively close circuited and -as the stops 58 of the upper manual are connected in the amplifying system as shown, the volume of sound elicited from the upper manual can be controlled relative to that desired to be had when playing the lower manual and said pedal keyboard. When the crescendo stops 88, 98 and I88 are close circuited, the volume of sound for full organ and crescendo effects can be controlled as desired by simultaneously depressing the aforementioned expression pedals. a

The impedance elements 19 are each variable from 0 to 2,000,000 ohms. The resistances 23 are each of the order of 2,000,000 ohms, the resistances 228 each of the order of 100,000 ohms and the resistances and 86, each of the order of 500,000 ohms. The synthesizing resistors 24 and 224 are each of the order of 100,000 ohms.

By reason of the relative values of the aforementioned resistances, correct additive efl'ects are had regardless of the number of playing keys simultaneously depressed and the number of stopsclose circuited at any instant. The term stops" used herein shall include any of the speaking Step Quality Range :3 Fund 23' 2nd 3rd 4th an em 7th 8th Upper manual.. 1 B 0 I 4 0 2 t 8 3 2 2 2 1 2 l6 6 a 1 o 0 0 0 0 0 0 Lower manual.. 1 8 0 4 0 2 3 3 2 2 2' 1 2 l6 s a 2 o 0 0 o 0 0 o 4 s c e .0 e 4 4 1 1 0 I 0 5 8 0 7 0 7 7 8 5 3 0 0 Pedal. 1 163 6 1 1 2 2 2 1 1 1 O 2 1 l6 s 4 3 0 c 0 0 0 0 0 3 Sub Tuba 16-8 5 7 6 7 6 6 5 3 0 0 The first crescendo stop 88 in the series of such stops for the upper manual is thus tapped to resistor 24 so that the relative intensities of the different partials will be as required for the production of a string and flute quality. The first crescendo stops 98 and I88 in the series of such stops forthe lower manual and the pedal keyboard are each tapped to a resistor 224 in such manner that the partials controlled by-the stop 98 will have their relative intensities graded for a string "and flute quality, whereas, the stop I 88. tapped as shown, willhave its partials correctly graded for a 'bourdon and string quality.

In Figure 3, I show an amplifying system 'condevelops an alternating current drop across the vimpedance element I9 at the output side of said alternator, the value of the impedance being adjustable from zero to approximately the maximum output of said alternator.

When the key switches are close circuited, volt- 7 ages flow through coacting bus-bars 28 to ground throughthe resistors 228, which function to produce an electrical relationship in the network between current and voltage such that the voltage drop across said resistors is always a function of the amount of current passing through them. Consequently, the intensity of any particular frequency at the bus-bars is approximately a linear function of the number of resisted paths between an alternator and said bus-bars, thereby insuring that the volume of output shall be a function of the number of notes simultaneously played and proportional to the number of speaking and crescendo stops close circuited at any instant, the resistors 28 and 86, serving to limit the transfer of energy from said bus-bars to an associated amplitude grading resistor. As the value of each of said resistors 25 and 86 is definitely calculated as herein stated, it follows that a single stop when close circuited draws only a small amount of available energy from said bus-bars, whereby when simultaneously playing a plurality of keys and close circuiting a plurality of stops, the number of resisted paths between said alternators and their coacting bus-bars proportionately increases in such manner that the total voltage drop across an associated amplitude grading resistor likewise proportionately increases.

The term speaking stop employed herein shall mean any stop other than the crescendo stops or any musically useful coupling of two or more stops.

What I claim as my invention is:

l. Mechanism for use in an electrical musical instrument employing selectors associated with different pitches and selector responsive means for translating into sound alternating current po tentials corresponding to said diflerent pitches; said mechanism comprising a set of stops, each of which is actuable to simultaneously render effective upon said translating means potentials corresponding to harmonic partials of a tone of predetermined timbre, and an actuator common to all stops of said set of stops for actuating said stops to effect translation of potentials in accordancewith a predetermined successive order in which tones of diflerent timbre are desired to be sounded.

2. Mechanism for use in an electrical musical instrument employing selectors associated with diiferent pitches and selector responsive means for translating into sound alternating current potentials corresponding to said different pitches; said mechanism comprising a set of stops, each of which is actuable to simultaneously render effective upon said translating means potentials corresponding to harmonic partials of a tone of predetermined timbre, and an actuator common to all stops of said set of stops for actuating said stops to eii'ect translation and addition of potentials in accordance with a predetermined successive order in which tones of different, timbre are desired to be sounded and including a foot pedal. the extent of depression of which determines the extent of addition 0! different timbres.

3. Mechanism for use in an electrical musical instrument employing electrical alternators for producing alternating current potentials corresponding to different pitches, an electrical transmitting network having an output circuit provided with an electro-acoustlc translating device for translating said potentials into audible sounds, and means in said net work by which the output energy thereof is proportional to the number of potentials at any frequency simultaneously transmitted through said network; said network comprising a set of stops connected in said network and each thereof actuable to simultaneously render effective upon said translating device from different alternators potentials corresponding to harmonic partials of a tone of predetermined timbre, and an actuator common to all stops of said set of stops for actuating said stops to eilfect translation of potentials in accordance with a predetermined successive order in which tones of diii'erent timbre are desired to be sounded.

JAMES MANA'I'I. 

